With the exception of the present Assignee, Syquest Technology, attempts to provide for a disc drive which can receive a removable cartridge containing data storage media have met with only limited success. Problems (1) inherent in providing a cartridge receiver mechanism for accurately aligning a cartridge and a disc with respect to read/write heads and a spindle motor, and (2) associated with loading and unloading read/write heads onto the disc without damage to either the heads or the disc, are difficult to design for as capacities are increased, and therefore place limitations on the amount of data that can be stored. As a further data storage limitation, the cartridges usually contain only one disc for data storage. Thus the market for such removable cartridge disc drives is a highly specialized one. Such drives are typically provided where the removable cartridge must be locked up between uses for security reasons.
On the high end of the spectrum, during the mid-nineteen-seventies, IBM introduced a Winchester drive (IBM 3340) with a removable data module having a capacity of 30 megabytes. This disc drive was used with large IBM mainframes and not with micro and personal computers. This data module used a plurality of 14-inch discs and weighed approximately 20 pounds. The disc drive had a complex mechanism with levers and gears to receive the data module. The data module required a number of connections to the disc drive in order for the module and drive to operate. First there needed to be a mechanical connector for transporting electrical signals between the drive and the data module. Then there were alignment devices such as docking pins to hold the data module in alignment with the drive. Further a spindle mechanism including a belt and pulley needed to be operably engaged with the module in order to spin the discs at an accurate speed. A mechanical connection needed to be made between a carriage which supported multiple read/write heads, which were positionable relative to the discs, and a voice coil actuator which was part of the drive. Finally a shutter mechanism had to be incorporated in order to allow the actuator mechanism to be insertable into the data module so that the actuator mechanism could engage with the carriage which supported the read/write heads.
Quite naturally, while such a device had commercial success, it was expensive and cumbersome to use and not suitable for the price-competitive low-end markets which demands the capabilities and performance of high-end machines. Further contamination of the discs and heads was possible due to the need to open the shutter mechanism each time the data module was engaged with the disc drive.
Another product manufactured by New World Computers had a data module with a five-megabyte storage capacity. As with the IBM 3340, the module had media, spindle and read/write heads, all located inside of the module. The heads were of a multiple element, fixed-arm design. This design was quite expensive to implement due to the multiple head elements required per disc surface, and had limited performance.
Considering the prior art, there is still a need for an accurate, relatively inexpensive, high capacity disc drive with a removable cartridge.